package require Ftclcauses the following to happen:
The following Tcl commands are created by this default Ftcl package to transfer information directly to the Fortran routines:
ftn_exec ftn_proc ?args
This command starts a Fortran routine "ftn_exec" that you need to write yourself. The first argument, "ftn_proc" is the name of the Fortran service that should be executed. It may have any number of additional arguments.
The return value is in-line with the Tcl conventions:
This command sets the configuration options. Currently, there are only
the debugging and trace options:
ftn_config debug returns the current debug mode
ftn_config debug true turns debugging on, and
ftn_config debug false turns it off.
ftn_config trace returns the current trace mode
ftn_config trace true turns tracing mode on (that is, all calls are reported; implies debugging output as well, but this may be set independently)
ftn_config trace false turns tracing mode off (the debug state is not affected).
In debugging mode, accessing variables and executing services is reported, including if it was successful (especially accessing non-existent variables is reported explicitly). In tracing mode all calls to the Fortran-accessible routines are reported.
PM: customising the interface
subroutine ftcl_exec( service, noargs, error ) character(len=*), intent(in) :: service integer, intent(in) :: noargs integer, intent(in) :: ierror ! ! Service: return a random number ! if ( service == 'random' ) then call random( rnd ) call ftcl_set_result( rnd ) endif ! ! Service: ... ! if ( service == '...' ) then ... endif ... end subroutine random( rnd ) implicit none real, intent(out) :: rnd call random_number( rnd ) end
If you are using a FORTRAN 77 compiler, then you will have to use the specific names.
The routine ftcl_get is the generic name of a set of related routines:
The implementation does not hide an essential difference in the handling of arguments though:
The service ftn_exec random is meant to return a random value using the Fortran 90 library routine, random_number.
subroutine ftcl_exec( ... ) ... ! ! Service: return a random number ! if ( service == 'random' ) then call random( rnd ) endif ! ! Service: ... ! if ( service == '...' ) then ... return end subroutine random( rnd ) use ftcl implicit none real, intent(out) :: rnd call random_number( rnd ) return end
The problem is that the result should be passed back to Tcl, either as a result string or as a change to the first argument. The first can be achieved by setting the result:
call ftcl_set_result( rnd )
The second can be achieved by assuming the first argument to be the name of a variable:
call ftcl_get_arg( 1, varname ) call ftcl_put( varname, rnd )